Last Thursday it was announced by NOAA that a Weak La Niña had formed in the Equatorial Pacific. Although it will remain fairly weak, its impacts could be felt here in Pennsylvania where we typically see many mixed precipitation events.
A La Niña raises the chance of an active northern stream. As a result, this season we will have an increased chance of experiencing storms originating in the Plains or Canada. There will likely be less than normal coastal storms. Unfortunately for those looking for a blizzard repeat, this means the chance of strong Nor’ Easters is low this winter.
As mentioned, many of the storms we encounter will form in the Central Plains and Canada. Since there is no major body of water in either area, this season will likely be full of small to moderate events similar to 2013-14. Below is a graphic to give you a better idea of northern stream storms.
Generally areas about 100 miles north of the low pressure see mainly snow. However, above the graphic shows low pressure tracks in the DC-Baltimore Area. This all depends on how deep the cold air is and the placement of a high pressure in Ontario.
If systems often track over the DC-Baltimore Area, Southern Pennsylvania will see many mixing events while Northern PA is on the snowier side. We think there is a good chance this happens several times during the upcoming season.
Another system that will occur often this season is the Alberta Clipper. These systems are almost often partnered with cold air, resulting in a frozen precipitation type on either side of the low pressure.
Below is a graphic of La Niña’s Potential Impacts On Pennsylvania this upcoming winter.
The northern third of the state is likely to see mainly snow events, the middle third could see mixing every so often but primarily snow events, and the southern third of PA will see mixed bags fairly often.
Don’t worry snow lovers, this does not impact our forecast snow totals for this Winter. Everything still remains on track.
As you can tell, this will be another difficult year of winter storm forecasting! Be sure to like Pennsylvania Weather Action on facebook for winter weather potentials to final call storm forecasts! Remember to hit that share button below, stay safe everyone!